Lou Reed and Laurie Anderson Wed

Legendary rocker Lou Reed married his longtime girlfriend, musician Laurie Anderson on April 12 in a quiet ceremony in Boulder, Colo. The couple, who has been together since 1995, held a quiet ceremony with two witnesses, Reed’s rep confirms to PEOPLE.

“It was very low-key,” the rep says of the ceremony, which was first reported by the New York Post.

On April 18, the newlyweds had a gathering of their closest friends to celebrate the union. Guests included director Julian Schnabel, music producer Hal Willner, and Law & Order: SVU star Richard Belzer.

“It was exactly what they wanted – an intimate gathering among friends,” the rep says. – Steve Helling